[Swlug] FW: RE: DIY Geiger counter

[peredur.net]

Reply from my contact in the radiation world.PeterSent from my Galaxy
-------- Original message --------From: Gareth Thomas <jgbcthomas at talktalk.net> Date: 12/03/2025  21:25  (GMT+00:00) To: "'peredur.net'" <peredur.net at gmail.com> Subject: RE: [Swlug] DIY Geiger counter Hi Peter Rhys seems like a keen electronics guy. What he describes is making a solid state photo luminescent ionising radiation detector rather than a much more basic ‘regular’ Geiger counter. It is a long time since I studied the electronics of radiation detectors so not sure I have the answers he is seeking, but I am pretty sure most Geiger counters don’t ‘store’ the electrical pulses, they just amplify them to a sufficient level to be able to register them on a needle or electronic display. Gareth  From: peredur.net [mailto:peredur.net at gmail.com] Sent: 06 March 2025 16:47To: Gareth Thomas <jgbcthomas at talktalk.net>Subject: FW: [Swlug] DIY Geiger counter The mail below cropped up in my inbox, and I thought, "Who do I know who works with radioactive materials?" Peter   Sent from my Galaxy  -------- Original message --------From: Rhys Sage via Swlug <swlug at mailman.lug.org.uk> Date: 06/03/2025 16:34 (GMT+00:00) To: South Wales Linux User Group <swlug at mailman.lug.org.uk> Cc: Rhys Sage <rhys_sage at yahoo.com> Subject: [Swlug] DIY Geiger counter  I'm in the middle of a project - to build a Geiger counter. It's a fun project so far.I have all the bits I need (I think) but as with all projects there's a lot of experimentation and changes made on the fly. I'm using a Thalium-doped Cesium Iodide crystal in combination with a BPX61 photo diode. For those that don't know- the BPX61 is slightly more sensitive to green light. The crystal emits blue/green light when struck by gamma radiation. Whether it emits light when struck by Alpha, Beta or X-Ray, I don't know. I do know there are other crystals more suited to those.The BPX61 output will feed into an OPA134PA amplifier and then that will in turn feed into a microcontroller. Given that the events generated by radioactive decay are very brief, would microcontroller speed make much difference? I could use an ATTiny13/ATTiny85 or something small like a micro RP2040 or an ESP32 C3 Super Mini.With a regular Geiger counter,does the system store the events somehow or does it just rely upon measuring maximum pulses when a pulse happens during a sampling period?Rhys Sage-- Swlug mailing listSwlug at mailman.lug.org.ukhttps://mailman.lug.org.uk/mailman/listinfo/swlug
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